1. Field of the Invention
The present invention relates to a stereomicroscope and in particular to a compact lightweight stereomicroscope suitable for observing and photographing an object with being carried outdoors.
2. Related Background Art
A compact lightweight stereomicroscope for magnifying and observing an object outdoors has been proposed, for example, in Japanese Patent Application Laid-Open No. 8-005931. The compact lightweight stereomicroscope makes it possible to be folded compact by turning an eyepiece tube member to face the eyepiece portion toward a stage upon being carried outdoors.
In photographing an object with an ordinary stereomicroscope, a so-called trinocular eyepiece tube is used, in which an optical path is divided by a beam splitter arranged in the optical path between objective lenses and eyepieces, and a camera is arranged on the divided optical path for a photographing optical system to take picture of the object. In this case, in order to secure stability upon equipping a camera, the weight of the base portion thereof is designed to be sufficiently heavy (see, for example, Japanese Patent Application Laid-Open No. 2002-267938).
Recently, a portable compact light weight stereomicroscope has been desired to be able to photograph as well as to observe an object. However, when a conventional photographing optical system using a trinocular eyepiece tube is used, since the tube portion for photographing is remained at all times even if photographing does not take place (while, for example, carrying or storing), the weight of the stereomicroscope increases, so that light weight for portability is spoiled. Moreover, when photographing takes place, since a camera for photographing has to be put on upper part of the microscope (in the vicinity of the upper part of the eyepiece tube), the center of gravity becomes high, so that it becomes easy to tumble. Furthermore, in a compact lightweight stereomicroscope, it is possible to observe an object by rotating a tube portion by substantially 90 degrees being in a state of horizontal position. However, when a camera is attached to the trinocular eyepiece tube, since the center of gravity varies in the horizontal direction, so that the stereomicroscope becomes easy to tumble.
In this manner, when a photographing optical system of a conventional trinocular eyepiece tube is applied to a compact lightweight stereomicroscope, light weight for portability and stability upon attaching a camera tend to be spoiled.